<p>Preserve blank lines in code blocks with tabs:</p>
<pre><code>a code block

two tabbed lines


three tabbed lines



four tabbed lines




five tabbed lines





six tabbed lines






End of tabbed block
</code></pre>
<p>And without tabs:</p>
<pre><code>a code block

two blank lines


three blank lines



four blank lines




five blank lines





six blank lines






End of block
</code></pre>
<p>End of document</p>